package team.background.network;

import java.io.IOException;
import java.io.OutputStream;
import java.io.Writer;


public class Base64 {
	
     private static final char[] S_BASE64CHAR = {
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',  
  'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',  
  'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',  
  'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',  
  'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',  
  'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',  
  '8', '9', '+', '/'
  };
     private static final char S_BASE64PAD = '=';
     private static final byte[] S_DECODETABLE = new byte[128];
   
    static {
    
    for (int i = 0; i < S_DECODETABLE.length; i ++)
  
    	S_DECODETABLE[i] = Byte.MAX_VALUE; // 127
  
      for (int i = 0; i < S_BASE64CHAR.length; i ++) // 0 to 63
      S_DECODETABLE[S_BASE64CHAR[i]] = (byte)i;
  }

  private static int decode0(char[] ibuf, byte[] obuf, int wp) {
   
	  int outlen = 3;
     if (ibuf[3] == S_BASE64PAD) outlen = 2;
     if (ibuf[2] == S_BASE64PAD) outlen = 1;
     int b0 = S_DECODETABLE[ibuf[0]];
     int b1 = S_DECODETABLE[ibuf[1]];
     int b2 = S_DECODETABLE[ibuf[2]];
     int b3 = S_DECODETABLE[ibuf[3]];
     switch (outlen) {
     
      case 1:
     obuf[wp] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
       return 1;
  case 2:
  obuf[wp++] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
  obuf[wp] = (byte)(b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
  return 2;
  case 3:
  obuf[wp++] = (byte)(b0 << 2 & 0xfc | b1 >> 4 & 0x3);
  obuf[wp++] = (byte)(b1 << 4 & 0xf0 | b2 >> 2 & 0xf);
  obuf[wp] = (byte)(b2 << 6 & 0xc0 | b3 & 0x3f);
  return 3;
  default:
  throw new RuntimeException("error");
  }
  }

  /**
  *
  */
  public static byte[] decode(char[] data, int off, int len) {
  char[] ibuf = new char[4];
  int ibufcount = 0;
  byte[] obuf = new byte[len/4*3+3];
  int obufcount = 0;
  for (int i = off; i < off+len; i ++) {
  char ch = data[i];
  if (ch == S_BASE64PAD
  || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
  ibuf[ibufcount++] = ch;
  if (ibufcount == ibuf.length) {
  ibufcount = 0;
  obufcount += decode0(ibuf, obuf, obufcount);
  }
  }
  }
  if (obufcount == obuf.length)
  return obuf;
  byte[] ret = new byte[obufcount];
  System.arraycopy(obuf, 0, ret, 0, obufcount);
  return ret;
  }

  /**
  *
  */
  public static byte[] decode(String data) {
  char[] ibuf = new char[4];
  int ibufcount = 0;
  byte[] obuf = new byte[data.length()/4*3+3];
  int obufcount = 0;
  for (int i = 0; i < data.length(); i ++) {
  char ch = data.charAt(i);
  if (ch == S_BASE64PAD
  || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
  ibuf[ibufcount++] = ch;
  if (ibufcount == ibuf.length) {
  ibufcount = 0;
  obufcount += decode0(ibuf, obuf, obufcount);
  }
  }
  }
  if (obufcount == obuf.length)
  return obuf;
  byte[] ret = new byte[obufcount];
  System.arraycopy(obuf, 0, ret, 0, obufcount);
  return ret;
  }

  /**
  *
  */
  public static void decode(char[] data, int off, int len, OutputStream ostream) throws IOException {
  char[] ibuf = new char[4];
  int ibufcount = 0;
  byte[] obuf = new byte[3];
  for (int i = off; i < off+len; i ++) {
  char ch = data[i];
  if (ch == S_BASE64PAD
  || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
  ibuf[ibufcount++] = ch;
  if (ibufcount == ibuf.length) {
  ibufcount = 0;
  int obufcount = decode0(ibuf, obuf, 0);
  ostream.write(obuf, 0, obufcount);
  }
  }
  }
  }

  /**
  *
  */
  public static void decode(String data, OutputStream ostream) throws IOException {
  char[] ibuf = new char[4];
  int ibufcount = 0;
  byte[] obuf = new byte[3];
  for (int i = 0; i < data.length(); i ++) {
  char ch = data.charAt(i);
  if (ch == S_BASE64PAD
  || ch < S_DECODETABLE.length && S_DECODETABLE[ch] != Byte.MAX_VALUE) {
  ibuf[ibufcount++] = ch;
  if (ibufcount == ibuf.length) {
  ibufcount = 0;
  int obufcount = decode0(ibuf, obuf, 0);
  ostream.write(obuf, 0, obufcount);
  }
  }
  }
  }

  /**
  * Returns base64 representation of specified byte array.
  */
  public static String encode(byte[] data) {
  return encode(data, 0, data.length);
  }

  /**
  * Returns base64 representation of specified byte array.
  */
  public static String encode(byte[] data, int off, int len) {
  if (len <= 0) return "";
  char[] out = new char[len/3*4+4];
  int rindex = off;
  int windex = 0;
  int rest = len-off;
  while (rest >= 3) {
  int i = ((data[rindex]&0xff)<<16)
  +((data[rindex+1]&0xff)<<8)
  +(data[rindex+2]&0xff);
  out[windex++] = S_BASE64CHAR[i>>18];
  out[windex++] = S_BASE64CHAR[(i>>12)&0x3f];
  out[windex++] = S_BASE64CHAR[(i>>6)&0x3f];
  out[windex++] = S_BASE64CHAR[i&0x3f];
  rindex += 3;
  rest -= 3;
  }
  if (rest == 1) {
  int i = data[rindex]&0xff;
  out[windex++] = S_BASE64CHAR[i>>2];
  out[windex++] = S_BASE64CHAR[(i<<4)&0x3f];
  out[windex++] = S_BASE64PAD;
  out[windex++] = S_BASE64PAD;
  } else if (rest == 2) {
  int i = ((data[rindex]&0xff)<<8)+(data[rindex+1]&0xff);
  out[windex++] = S_BASE64CHAR[i>>10];
  out[windex++] = S_BASE64CHAR[(i>>4)&0x3f];
  out[windex++] = S_BASE64CHAR[(i<<2)&0x3f];
  out[windex++] = S_BASE64PAD;
  }
  return new String(out, 0, windex);
  }

  /**
  * Outputs base64 representation of the specified byte array to a byte stream.
  */
  public static void encode(byte[] data, int off, int len, OutputStream ostream) throws IOException {
  if (len <= 0) return;
  byte[] out = new byte[4];
  int rindex = off;
  int rest = len-off;
  while (rest >= 3) {
  int i = ((data[rindex]&0xff)<<16)
  +((data[rindex+1]&0xff)<<8)
  +(data[rindex+2]&0xff);
  out[0] = (byte)S_BASE64CHAR[i>>18];
  out[1] = (byte)S_BASE64CHAR[(i>>12)&0x3f];
  out[2] = (byte)S_BASE64CHAR[(i>>6)&0x3f];
  out[3] = (byte)S_BASE64CHAR[i&0x3f];
  ostream.write(out, 0, 4);
  rindex += 3;
  rest -= 3;
  }
  if (rest == 1) {
  int i = data[rindex]&0xff;
  out[0] = (byte)S_BASE64CHAR[i>>2];
  out[1] = (byte)S_BASE64CHAR[(i<<4)&0x3f];
  out[2] = (byte)S_BASE64PAD;
  out[3] = (byte)S_BASE64PAD;
  ostream.write(out, 0, 4);
  } else if (rest == 2) {
  int i = ((data[rindex]&0xff)<<8)+(data[rindex+1]&0xff);
  out[0] = (byte)S_BASE64CHAR[i>>10];
  out[1] = (byte)S_BASE64CHAR[(i>>4)&0x3f];
  out[2] = (byte)S_BASE64CHAR[(i<<2)&0x3f];
  out[3] = (byte)S_BASE64PAD;
  ostream.write(out, 0, 4);
  }
  }

  /**
  * Outputs base64 representation of the specified byte array to a character stream.
  */
  public static void encode(byte[] data, int off, int len, Writer writer) throws IOException {
  if (len <= 0) return;
  char[] out = new char[4];
  int rindex = off;
  int rest = len-off;
  int output = 0;
  while (rest >= 3) {
  int i = ((data[rindex]&0xff)<<16)
  +((data[rindex+1]&0xff)<<8)
  +(data[rindex+2]&0xff);
  out[0] = S_BASE64CHAR[i>>18];
  out[1] = S_BASE64CHAR[(i>>12)&0x3f];
  out[2] = S_BASE64CHAR[(i>>6)&0x3f];
  out[3] = S_BASE64CHAR[i&0x3f];
  writer.write(out, 0, 4);
  rindex += 3;
  rest -= 3;
  output += 4;
  if (output % 76 == 0)
  writer.write("\n");
  }
  if (rest == 1) {
  int i = data[rindex]&0xff;
  out[0] = S_BASE64CHAR[i>>2];
  out[1] = S_BASE64CHAR[(i<<4)&0x3f];
  out[2] = S_BASE64PAD;
  out[3] = S_BASE64PAD;
  writer.write(out, 0, 4);
  } else if (rest == 2) {
  int i = ((data[rindex]&0xff)<<8)+(data[rindex+1]&0xff);
  out[0] = S_BASE64CHAR[i>>10];
  out[1] = S_BASE64CHAR[(i>>4)&0x3f];
  out[2] = S_BASE64CHAR[(i<<2)&0x3f];
  out[3] = S_BASE64PAD;
  writer.write(out, 0, 4);
  }
  }
}